High-pressure arc



Aug. 4, 19 25. v

' W. E. STORY,. JR

HIGH PRESSURE ARC Filed Jul 5, 19 g [mm/enter- WiHiamw Efitory Jn,

His Attorney.

: equipment in which an arc-light isus Patented Aug. 4, 1925.

UNITED STATES- PATENT OFFICE.

WILLIAM' E. STORY .13., 01 WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A C ORPORA,TION OF NEW YQBK.

Bren-PRESSURE ABC.

' Application filed m 5,

invented certain new and useful Improvements in High-Pressure Arcs, of which the following is a specification.

My. invention relates to light projectm the are being maintained in a chamber containing gas above atmospheric pressure. This invention is especially adapted for use in connection with moving picture projectors, spotlights and the like.

a It is well known that the intrinsic brilliancy of the arc increases with the pressure of the medium in which it is maintained. Heretofore efforts have been made to produce a practical equipment embodying an arc-light under pressure but inas-.

much as the arc has-to be set up within an opaque pressure chamber of steel or the like, a window with a pane of glass or other transparent material has to be provided throughwhich the light passes to the screen or other point where the light is wanted. In such equipment of the prior artthe condenser lens is .outside the pressure chamber and therefore to obtain a maximum brilliancy at the point wanted the arc must be brought as near the window as possible.

When this is done the window becomes exthat-has been heretofore employed to enable the arc to beset further back from the window. In this construction a'larger window is, employed with the framework having a number of small openings each of which is covered or sealed with a. window pane, each pane being small enoughto withstand the pressure, but this construction is objectionable for the reason that the framework ofthe window cuts oil a large per-,

cent of the light. It is one of-the ob'ects of my invention to provide means wit pressure chamber for collecting the diverging rays of the are and sending as many through the small window arrangetheb 1922. Serial No. 572,945.

ment with the arc set back with the are close up to the window with the lens on the outside. With this arrangement I avoid the excessive heating of the window pane and reduce to a minimum the .liabilit of having the by-products of the arc deposit on the window which deposit of course reduces the amount of light transmitted.

In order to further minimize the liability of such deposit and to keep the chamberv cooler than otherwise would be the case, I

alsopropose to -fprovide means for causing a circulation o the gas in the pressure chamberto take place, the direction of the circulation being away from the window and away from the lens and toward an exit located in the rear of the pressure chamber. This arrangement will'enable'the by-prodnets of the arc to be carried off at the same time that the result of cooling is obtained.

I also contemplate other details of improvement which will more fully appear from the following specification wherein all means which I propose to employ are more fully set forth and claimed, reference being had to the accompanying drawing. In the said drawing the figure shows the pressure chamber in sectional elevation and it also shows apparatus by means of which a circulation of the gas is produced and maintained.

Referring more in particular to the said drawing, the housing 2 contains the pressure chamber 3 in which the arc-lamp is located and in which the electrodes 4 and 5 of the arc-light are also located. It will be understood of course that suitable electrical lens will be heated by the are but inasmuch as the lens is inside the chamber the distribution of the heat ismore' uniform which of course makes it safer. other words, there is less liability of cracking the lens by ringing it close to the arcinside of the chamber than there is of cracking the window by bringing the are close to the window. In connection with this pressure chamber, I provide a gas reservoir 8 containing gas at higher ressure than the pressure maintained in t e chamber 3. From this reservoir pipe lines 9 are provided which supply gas to the chamber 3. The gas is forced through the chamber and out of the valve 10 shown near the upper right hand portion of the chamber, thus producing a circulation which keeps down the tem perature and at the same time drives out through the valve the by-products of the are as heretofore pointed out. Therefore 7 the by-products are prevented from depositing in the chamber and particularly on the lens window. It will be understood thatthe valve 10 may be of any suitable construe tion; an ordinary safety valve, for example, will serve the purpose. Just at the point where the pipes 9 terminate at the housing 2 I provide check valves 11 which also may be of any suitable construction that will permit gas to go irito the chamber 3, but which will prevent flow in the reverse direction; that is, from the chamber into the pipes 9. Between the reservoir 8 and the valves 11 I provide a shut. ofi' valve 12 for regulating the rate of flow into the chamber 3 from the reservoir To the right of the reservoir I have shown a pump 13 which may be of any suitable construction for maintaining a constant pressure in the reser voir 8. Therefore by the use of such simple and efi'ective means as described, I am en abled to accom lish the results heretofore pointed out an to avoid the objections to which I have referred.

What I claim as new and desire to secure by Letters Patent of the United States, is A light projector comprising a sealed chamber, a transparent window in the wall of said chamber, an arc lamp within said chamber, a condensing lens located between. the are and the window for collecting rays of light from the arc and directing them through the window, an inlet valve together with an outlet valve for said chamber, means for supplying gas under pressure to operate the intake valve whereby gas may be forced into the chamber so that the arc may be operated under ressure to increase its brilliance and where y the outlet valve may be operated when a predetermined pressure. is obtained for maintaining the pressure in the chamber constant and for producing circulation within the chamber. In witness whereof, I have hereunto set my hand this 5th da of July, 1922.

. WILL AM E. STORY, JR. 

